AddDockerfile: Fix Connectivity Issue: Cannot Assign Requested Address for

[aitrailblazer]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Problem Description

Error in Connectivity

• The application attempts to connect to localhost:8000 but fails with the error:
  Cannot assign requested address

• This issue stems from the inability of the SECEdgarWSAppService to reach the expected container's HTTP endpoint.

Retry Attempts

• The system retries connecting 5 times, each with a fixed delay and jitter (as configured), but ultimately fails.

Logs

• Application logs indicate:
• It successfully connects to the container webfrontend.
• However, no CIK (Central Index Key) is found for the ticker TSLA.

---

Components Overview

Docker Setup

A Docker container (secedgarwsapp) runs a Python app to handle SEC filings. Key features:

• ASGI Server: Uses Uvicorn to expose the app on port 8000.
• Networking: The container is configured to use localhost as the default BASE_ADDRESS.

Dockerfile Highlights

• The app exposes port 8000.
• It runs as a non-root user for better security.
• Uses Uvicorn to serve main:app.

Service Configuration in my.Web

HttpClient

• Configured to communicate with the SEC Edgar Web Service at http://localhost:8000.
• Implements resilience policies:
• Retries
• Timeouts
• Circuit breaking

Program.cs in my.AppHost

The secedgarwsapp service:

• Exposes port 8000 both internally and externally.
• Uses OpenTelemetry for observability.
• Is marked as a dependency for the webfrontend project.

GetCIKAsync Method

This method:

• Sends a GET request to fetch the CIK for a given ticker.
• Implements basic validation for tickers.
• Gracefully handles potential HTTP or parsing errors.

---

Connecting...
2025-01-21T17:57:13.07790  Connecting to the container 'webfrontend'...
2025-01-21T17:57:13.16873  Successfully Connected to container: 'webfrontend' [Revision: 'webfrontend--0000049-6c5c7c8df5-kn7lw', Replica: 'webfrontend--0000049']
      Execution attempt. Source: 'SECEdgarWSAppService-standard//Standard-Retry', Operation Key: '', Result: 'Cannot assign requested address (localhost:8000)', Handled: 'True', Attempt: '5', Execution Time: 0.987ms
      System.Net.Http.HttpRequestException: Cannot assign requested address (localhost:8000)
       ---> System.Net.Sockets.SocketException (99): Cannot assign requested address
         at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken)
         at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource.GetResult(Int16 token)
         at System.Net.Sockets.Socket.<ConnectAsync>g__WaitForConnectWithCancellation|285_0(AwaitableSocketAsyncEventArgs saea, ValueTask connectTask, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)
         --- End of inner exception stack trace ---
         at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.InjectNewHttp11ConnectionAsync(QueueItem queueItem)
         at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
         at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.<SendCoreAsync>g__Core|4_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
         at Microsoft.Extensions.Http.Resilience.ResilienceHandler.<>c.<<SendAsync>b__3_0>d.MoveNext()
HTTP request error: Cannot assign requested address (localhost:8000)
info: aitrailblazer.Web.Components.Pages.AIFilingScout[0]
      No CIK found for ticker TSLA. Skipping further processing.

my.AppHost/Program.cs

var secedgarwsapp = builder.AddDockerfile("secedgarwsapp", "./sec-edgar-ws")
    //.WithHttpEndpoint(targetPort: 8000, env: "PORT") // Expose HTTP endpoint based on PORT environment variable
    .WithHttpEndpoint(targetPort: 8000, port: 8000, name: "secedgarwsapp-http") // Bind host port 8000 to container port 8000
    .WithExternalHttpEndpoints()  // Make it accessible externally
    .WithOtlpExporter();          // Enable OpenTelemetry for observability

builder.AddProject<Projects.aitrailblazer_Web>("webfrontend")
    .WithExternalHttpEndpoints()
    .WithReference(apiService)
    .WaitFor(secedgarwsapp);      /
//
builder.Build().Run();

my.AppHost/Dockerfile

# Use an official Python runtime as the base image
FROM python:3.11-slim

# Set environment variables to avoid interactive prompts during apt-get
ENV DEBIAN_FRONTEND=noninteractive

# Set the working directory inside the container
WORKDIR /app

# Install system dependencies required by WeasyPrint
RUN ...

# Copy the requirements file to the container
COPY requirements.txt requirements.txt

# Install Python dependencies
RUN pip install --upgrade pip && pip install --no-cache-dir -r requirements.txt

# Copy the application code to the container
COPY . .

# Expose the port that the app runs on
EXPOSE 8000

# Set environment variables for Uvicorn
ENV PORT=8000
ENV HOST=0.0.0.0

# Use non-root user for better security
RUN addgroup --system appgroup && adduser --system --group appuser
USER appuser

# Command to run the app using Uvicorn ASGI server
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000", "--log-level", "info"]

my.Web
Program.cs

builder.Services.AddHttpClient<SECEdgarWSAppService>(client =>
{
    client.BaseAddress = new Uri("http://localhost:8000"); // or 0.0.0.0

    client.Timeout = TimeSpan.FromMinutes(5); // Total timeout for all retries combined
})
.AddStandardResilienceHandler(options =>
{
    // Retry policy configuration
    options.Retry.MaxRetryAttempts = 5; // Retry up to 5 times
    options.Retry.Delay = TimeSpan.FromSeconds(2); // Fixed delay between retries
    options.Retry.UseJitter = true; // Add jitter to avoid retry storms

    // Timeout policy configuration
    options.AttemptTimeout.Timeout = TimeSpan.FromSeconds(60); // Timeout for individual attempts

    // Total request timeout (all retries combined)
    options.TotalRequestTimeout.Timeout = TimeSpan.FromMinutes(5);

    // Circuit breaker configuration
    options.CircuitBreaker.SamplingDuration = TimeSpan.FromSeconds(120); // At least double the attempt timeout
});

SECEdgarWSAppService.cs

 public async Task<string?> GetCIKAsync(string ticker)
    {
        try
        {
            // Validate ticker format before making the request
            if (string.IsNullOrWhiteSpace(ticker) || !System.Text.RegularExpressions.Regex.IsMatch(ticker, @"^[A-Za-z0-9]+$"))
            {
                Console.WriteLine("Invalid ticker format. Only alphanumeric characters are allowed.");
                return string.Empty; // Return empty string for unexpected errors
            }

            // Construct the endpoint URL for fetching the CIK
            string endpoint = $"/cik/{ticker}";

            // Send a GET request to the endpoint
            var response = await _httpClient.GetAsync(endpoint);

            // If the response status is 404 (Not Found), return null
            if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
            {
                Console.WriteLine($"Ticker not found: {ticker}");
                return string.Empty; // Return empty string for unexpected errors
            }

            // Ensure the request was successful
            response.EnsureSuccessStatusCode();

            // Parse the response as plain text
            var cik = await response.Content.ReadAsStringAsync();

            // Validate the CIK
            if (string.IsNullOrWhiteSpace(cik) || !long.TryParse(cik, out _))
            {
                Console.WriteLine("Invalid or empty CIK returned by the server.");
                return string.Empty; // Return empty string for unexpected errors
            }

            // Log the retrieved CIK
            Console.WriteLine($"Fetched CIK for {ticker}: {cik}");

            return cik;
        }
        catch (HttpRequestException httpEx)
        {
            // Log the HTTP request error
            Console.WriteLine($"HTTP request error: {httpEx.Message}");
            return string.Empty; // Return empty string for unexpected errors
        }
        catch (Exception ex)
        {
            // Log any unexpected error
            Console.WriteLine($"Unexpected error: {ex.Message}");
            return string.Empty; // Return empty string for unexpected errors
        }
    }

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version info

No response

Anything else?

No response

[davidfowl]

Your web front end is trying to call your python container, but it's using localhost to talk to the python container? Why are you using localhost instead of http://secedgarwsapp?

[aitrailblazer]

I tried but couldn't be found. How you will do it?

[davidfowl]

Change this code:

var secedgarwsapp = builder.AddDockerfile("secedgarwsapp", "./sec-edgar-ws")
    //.WithHttpEndpoint(targetPort: 8000, env: "PORT") // Expose HTTP endpoint based on PORT environment variable
    .WithHttpEndpoint(targetPort: 8000, port: 8000, name: "secedgarwsapp-http") // Bind host port 8000 to container port 8000
    .WithExternalHttpEndpoints()  // Make it accessible externally
    .WithOtlpExporter();          // Enable OpenTelemetry for observability

builder.AddProject<Projects.aitrailblazer_Web>("webfrontend")
    .WithExternalHttpEndpoints()
    .WithReference(apiService)
   .WithReference(secedgarwsapp.GetEndpoint("secedgarwsapp-http"))
    .WaitFor(secedgarwsapp);    

Then it should work.

PS: The documentation explains the pattern https://learn.microsoft.com/en-us/dotnet/aspire/fundamentals/app-host-overview?tabs=docker#connection-string-and-endpoint-references

[aitrailblazer]

in my.Web:

builder.Services.AddHttpClient<SECEdgarWSAppService>(client =>
{
    client.BaseAddress = new("http://secedgarwsapp-http:8000");

    client.Timeout = TimeSpan.FromMinutes(5); // Total timeout for all retries combined
})

calling it:

2025-01-22T10:14:33       Execution attempt. Source: 'SECEdgarWSAppService-standard//Standard-Retry', Operation Key: '', Result: 'nodename nor servname provided, or not known (secedgarwsapp-http:8000)', Handled: 'True', Attempt: '0', Execution Time: 12.9737ms
2025-01-22T10:14:33       System.Net.Http.HttpRequestException: nodename nor servname provided, or not known (secedgarwsapp-http:8000)

[davidfowl]

client.BaseAddress = new("http://secedgarwsapp-http);

Remove the port

[aitrailblazer]

builder.Services.AddHttpClient<SECEdgarWSAppService>(client =>
{
    client.BaseAddress = new("http://secedgarwsapp-http");

    client.Timeout = TimeSpan.FromMinutes(5); // Total timeout for all retries combined
})

2025-01-22T11:14:52       Execution attempt. Source: 'SECEdgarWSAppService-standard//Standard-Retry', Operation Key: '', Result: 'nodename nor servname provided, or not known (secedgarwsapp-http:80)', Handled: 'True', Attempt: '0', Execution Time: 126.1177ms
2025-01-22T11:14:52       System.Net.Http.HttpRequestException: nodename nor servname provided, or not known (secedgarwsapp-http:80)

[davidfowl]

Sorry, I meant:

var secedgarwsapp = builder.AddDockerfile("secedgarwsapp", "./sec-edgar-ws")
    .WithHttpEndpoint(targetPort: 8000, port: 8000) // Bind host port 8000 to container port 8000
    .WithExternalHttpEndpoints()  // Make it accessible externally
    .WithOtlpExporter();   

builder.Services.AddHttpClient<SECEdgarWSAppService>(client =>
{
    client.BaseAddress = new("http://secedgarwsapp");

    client.Timeout = TimeSpan.FromMinutes(5); // Total timeout for all retries combined
})

Change both of the following.

[aitrailblazer]

var secedgarwsapp = builder.AddDockerfile("secedgarwsapp", "./sec-edgar-ws")
    .WithHttpEndpoint(targetPort: 8000, port: 8000) // Bind host port 8000 to container port 8000
    .WithExternalHttpEndpoints()  // Make it accessible externally
    .WithOtlpExporter();

builder.AddProject<Projects.aitrailblazer_Web>("webfrontend")
    .WithExternalHttpEndpoints()
    .WithReference(apiService)
    .WaitFor(secedgarwsapp);

builder.Services.AddHttpClient<SECEdgarWSAppService>(client =>
{
    client.BaseAddress = new("http://secedgarwsapp");

    client.Timeout = TimeSpan.FromMinutes(5); // Total timeout for all retries combined
})

2025-01-22T12:18:04       Sending HTTP request GET http://secedgarwsapp/cik/T
2025-01-22T12:18:04 warn: Polly[3]
2025-01-22T12:18:04       Execution attempt. Source: 'SECEdgarWSAppService-standard//Standard-Retry', Operation Key: '', Result: 'nodename nor servname provided, or not known (secedgarwsapp:80)', Handled: 'True', Attempt: '0', Execution Time: 185.1847ms
2025-01-22T12:18:04       System.Net.Http.HttpRequestException: nodename nor servname provided, or not known (secedgarwsapp:80)
2025-01-22T12:18:04        ---> System.Net.Sockets.SocketException (0xFFFDFFFF): nodename nor servname provided, or not known

[davidfowl]

Is your application using service discovery? Are service defaults added to the project?

[aitrailblazer]

yes:

myWeb.csproj

    <ProjectReference Include="..\my.ServiceDefaults\my.ServiceDefaults.csproj" />

my.ServiceDefaults is not changed. it was generated when I created the project.

[davidfowl]

There should be a call in your application to AddServiceDefaults, that's the logic that wires up service discovery.

[aitrailblazer]

myWeb.
Program.cs
var builder = WebApplication.CreateBuilder(args);
builder.AddServiceDefaults();

   Start processing HTTP request GET http://secedgarwsapp/cik/TSLA
2025-01-22T13:47:35 info: System.Net.Http.HttpClient.SECEdgarWSAppService.ClientHandler[100]
2025-01-22T13:47:35       Sending HTTP request GET http://secedgarwsapp/cik/TSLA
2025-01-22T13:47:35 warn: Polly[3]
2025-01-22T13:47:35       Execution attempt. Source: 'SECEdgarWSAppService-standard//Standard-Retry', Operation Key: '', Result: 'nodename nor servname provided, or not known (secedgarwsapp:80)', Handled: 'True', Attempt: '0', Execution Time: 6.4582ms

[aitrailblazer]

This solution is working:

my.AppHost
Program.cs

var secedgarwsapp = builder.AddDockerfile(
    "secedgarwsapp", 
    "./sec-edgar-ws", // The directory where your backend project and Dockerfile are located
    "Dockerfile"
).WithHttpEndpoint(8000, 8000); // Map container's port 80 to host's port 5000


builder.AddProject<Projects.aitrailblazer_Web>("webfrontend")
    .WithExternalHttpEndpoints()
    .WithReference(apiService)
    .WithReference(secedgarwsapp.GetEndpoint("http"));

my.Web
Program.cs

builder.Services.AddHttpClient<SECEdgarWSAppService>(client =>
    {
        // This URL uses "https+http://" to indicate HTTPS is preferred over HTTP.
        // Learn more about service discovery scheme resolution at https://aka.ms/dotnet/sdschemes.
        client.BaseAddress = new("https+http://secedgarwsapp");
    });

[davidfowl]

Excellent!